Using hand performance measures to predict handedness.

Handedness is defined by the individual's preference to use one hand predominately for unimanual tasks and the ability to perform these tasks more efficiently with one hand (Corey, Hurley, & Foundas, 2001). It is important to use performance variables to measure handedness because they are more objective than traditional hand preference questionnaires (Bryden, Pryde, & Roy, 2000a). The current study develops a predictive model of handedness as measured by the Waterloo Handedness Questionnaire (WHQ) using several performance indicators of handedness. A total of 120 individuals (60 right-handers and 60 left-handers) were asked to complete four performance-based tasks: the Grooved Pegboard (GP), the Annett pegboard (AP), finger tapping (FT), and grip strength (GS) as well as an observational measure of preference, the Wathand Box Test (WBT). Backward linear regression analysis showed that the Wathand Box measure and the laterality quotients for several performance measures (GP place, AP, and FT) combined to act as the most accurate predictors of hand preference. The predictive model of handedness developed is as follows: WHQ = -2.760- - 0.667(GP place) + 0.809(FT) + 0.234(WBT) - 0.748(AP) with an explained variance of 0.836. These results illustrate, as Corey et al. (2001) suggested, that the best predictive model of handedness combines preference measures and several performance measures that tap into different elements of motor performance. By developing this model, it is possible to get an accurate measure of handedness using objective measures.